The invention relates to a simple, reliable system for automatically dosing vehicle fuel tanks with a fuel additive, particularly a concentrate containing a fuel borne catalyst (FBC), using gravity as the means of providing a constant flow into the fuel, preferably with no electronics or complex mechanical parts.
Fuel additives are known in the art to provide improvements in combustion, handling and storage characteristics of fuels such as gasoline, diesel and alternative and bioderived fuels used in internal combustion engines. Exemplary additives used to control engine deposits, improve cold flow characteristics, promote more complete in-cylinder combustion or regenerate a diesel particulate filter.
The invention relates to simple mechanical devices that enable a simple and reliable introduction of a fuel additive into the fuel tank when fueling a vehicle, particularly one powered by a medium or light duty diesel engine. Fuel additives, especially FBC's in the form of concentrates containing platinum group metals, cerium, iron, copper, manganese, magnesium and the like or combinations, can enable cleaner burning of a fuel in an engine, thereby allowing for more efficient operation of the engine. The additives can also reduce pollutants as a primary measure or in combination with an after treatment device.
While additives can be added to the fuel at any point in the distribution chain including at the refinery or bulk storage terminal, there are many cases where addition of additives to specific vehicle fuel tanks is desired. Vehicles equipped with diesel particulate filters can rely on fuel borne catalyst additives to regenerate filters; however not all vehicles in a fleet may have filters and therefore additive treated fuel may be desired for a select group of vehicles. In other cases vehicles may fuel away from a home terminal at retail fuel outlets where additive treatment may not be available at the fuel dispensing site. With this system, vehicles are free to fuel to fuel at any location and still receive treated fuel.
Many prior art systems proposed for dosing additives involve complex monitoring electronically and/or mechanically to achieve the desired concentration of active catalytic metals in the fuel. The provision of systems that require modifications to fuel tanks or to wiring harnesses are not practical for retrofit applications due to the great variety of trucks being used commercially, even by a single fleet owner. On board dispensing systems mounted on a vehicle are known in the art and generally include a reservoir to store liquid additive on the vehicle to treat a known amount of fuel. These systems typically involve measurement of fuel level in the fuel tank using floats or sensors and the use of hydraulic or electric pump and metering systems to dispense additive from the reservoir into the fuel tank or fuel feed line to or from the engine. Other systems can inject pulses of additive under pressure at preset time intervals or as a function of engine operation by using an electronically controlled solenoid valve or pulsed pumping system. These systems all involve sophisticated and expensive electronics, pumps, controllers and sensors to meter the additive and often lead to high or low additive concentrations in the fuel tank as fuel level rises or falls due to addition or consumption of fuel. this system does not require any of these parts.
Yet other prior art systems require operator monitoring and/or intervention. However, fleet operators need the assurance that an FBC additive concentrate is being properly added to the fuel of designated vehicles without requiring a particular operator to perform any task other than his normal fueling operation. Operator monitoring or intervention can be problematic, especially where the same vehicle is used by different operators.
Current and proposed regulations challenge manufacturers to both achieve good fuel economy and reduce emissions. While fuel additives will likely be necessary to achieve the objectives of the regulations, the art has provided no simple device capable of metering an effective additive into the fuel in a reliable manner with no operator intervention or attention.
What is needed is a simple mechanical additive dosing system that dispenses additive into the fuel in proportion to the fuel being added to the fuel tank of an internal combustion engine.